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Upgrading spotlights to LED

I’ve got a couple of 12V halogen spot lights on the hallway of my apartment. I rarely turn them on because other lights usually service the area. This made me think that I could just make them dimmer and leave them on the whole night, so I’ve found a simple method to replace the bulb and mirror with a LED. The choice is orange, because i already had them and because orange light seems more pleasant while waking up at night for a fridge walk.

The spot lights, coming from Ikea, were quickly stripped of the bulb and mirror. The resulting space was big enough to allow me to install the LED and a small heatsink make of two used L shaped aluminum profiles. I’ve used thermal paste for the LED and between the aluminum brackets and glue to fix everything to the back of the spot light. Plastic washers ensured the screws didn’t create a short considering how the screws were mounted.

The LEDs used here are 350mA types, but I made a constant current supply to use them at about 160mA because this provided good enough lighting. In this setup, even in the closed spot light, the heatsink barely heats which means that there is adequate cooling. Power is ensured by an old 9V transformer at the moment (I’m thinking that the original 20W electronic transformer might do the job if I add a rectifier at the output).

For future use I’m thinking of hooking up a PIR sensor so that they will light more when someone is passing by or a light level sensor for automatic turn on.

9 comments to Upgrading spotlights to LED

[…] The hallway spotlights got new white LEDs as well and a light sensor. Tiny PIR sensors will turn on the lights in the kitchen and bathroom when someone comes in range. The sensors are rather popular modules using a BISS0001 IC; they provide a 3.3V level for an adjustable time when motion is detected. […]

I’ve used a simple constant current source, like the first under Two transistor constant current supply from here: http://www.electrobob.com/linear-led-power-supplies/ . The parts used are
R1: 2.2K
RS: 4.1 ohm made of two 8.2 ohm in parallel
T2: BC547
T1: BD139